Investigations of the formation, representation, and organization of concepts have been central to the field of cognitive psychology over the past several decades. One dominant theory of semantic memory (Allport, 1985) describes object concepts as distributed mental representations implemented in functionally and physically distinct attribute-domains that correspond to different sensory or motor domains of which they are also a part. In fact, according to Allport, these modules are the very same areas of the brain that are dedicated to processing sensorimotor information. One such attribute-domain that has been discussed extensively in the cognitive and cognitive neuroscience literatures is the domain of visual knowledge. This attribute-domain is the topic of investigation in the current proposal. Specifically, we aim (1) to characterize visual knowledge attribute-domains and, in particular, to examine subdivisions in conceptual representations about object appearance that parallel subdivisions in visual perception;(2) to explore variation in visual knowledge retrieval across different concepts and categories;(3) to investigate the link between visual knowledge and visual perception;and, (4) to relate individual differences in visual knowledge attribute-domains to variation in behavior and experience. The proposed experiments make use of a variety of methodologies, including behavioral experiments in normal subjects, congenitally blind adults, and brain-damaged patients, and neuroimaging experiments in both normal and congenitally blind subjects.